| Aviation hydraulic actuator is an important part of aircraft actuator system and flight control system.Hydraulic actuator has quickly become a mainstream aircraft actuator system because of its high reliability,high power density,mature technology and other advantages.The sealing system is the core component of hydraulic actuator,and its sealing performance directly affects the stability and safety of aircraft operation.Therefore,it is of great practical significance to carry out theoretical and experimental studies of lip sealing.A series of studies on actuator cylinder sealing systems are presented in this paper through theoretical analysis,numerical simulations,and experimental measurements.The research results further clarify the working mechanism of the seal,improve the reliability of the seal system,and have important engineering guiding value.The actuator has two seals,respectively piston seal and piston rod seal;A PS seal containing 3 sections of seal lip was used in the piston seal.According to its special seal form,a numerical model for multi-lip reciprocating slip ring combined seal was constructed.The numerical model includes solid mechanics analysis,fluid mechanics analysis,contact mechanics analysis and fluid-structure coupling analysis.Taking the PS seal with three sealing lips as an example,the oil film thickness distribution,oil film pressure distribution,rough peak contact pressure distribution,internal and external travel flow and friction at the sealing interface were obtained based on the numerical model.The problem of difficult determination of boundary conditions in multi-lip seals is solved,and the boundary conditions of each seal lip in steady-state operation are obtained by iterative calculations.The sealing mechanism of multi-lip seals is clarified,and a theoretical system and method for the research in the field of reciprocating multi-lip seals are formed,which is of great scientific significance.The seal used in the landing gear actuator rod seal is a shaft VL type combination seal.The rubber-plastic combination seal is composed of a rubber ring and a plastic seal ring,and the deformation of the plastic ring during installation has an important impact on the sealing performance.In this paper,we take the shaft VL type combination seal as an example,based on the 3D finite eleiment simulation model and visualization seal assembly bench to study the assembly process of different processes.We use finite element simulation to restore the seal assembly process,build a visual seal assembly bench,conduct seal assembly tests,extract key parameters such as seal interface contact pressure and contact width,and evaluate the seal performance;establish the relationship between seal performance and assembly process,optimize the seal installation and correction process,and solve the randomization and empirical problems of the assembly process.The VL seal of the landing gear actuator piston rod has a small contact area and a high lip contact pressure,which is prone to wear;this leads to a change in the lip profile,which changes the contact characteristics between the seal ring and the shaft,resulting in changes in static contact pressure and contact width,which in turn affects the seal performance.Numerical wear simulation analysis is carried out for VL seal to predict the seal lip wear and its service life;the research results are of certain engineering guidance value. |
PDF Full Text Request